Data Assist Sort Table Data

Data Assist Sort Table Data

I have a repeating table with 3 column of data. I have followed the tutorial in the solution recipies on how to "Sort By Column Links". I have successfully finished the tutorial but I need help with the following:

I would like to have 4 custom links (instead of just two toggling links) in a dropdown menu:

Looking at the code generated by the tutorial, i cannot understand what I should make the links in the dropdown be to accomplish the ASC or DESC part. Is there anyway to handle the ASC/DESC in the link and not just rely on the toggle function?